INSECTS PRODUCING HONEYDEW EXPLOITED BY BEES IN GREECE Loukas A. Santas To cite this version: Loukas A. Santas. INSECTS PRODUCING HONEYDEW EXPLOITED BY BEES IN GREECE. Apidologie, Springer Verlag, 1983, 14 (2), pp.93-103. hal-00890589 HAL Id: hal-00890589 https://hal.archives-ouvertes.fr/hal-00890589 Submitted on 1 Jan 1983 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. INSECTS PRODUCING HONEYDEW EXPLOITED BY BEES IN GREECE LOUKAS A. SANTAS Department ot’ Agricultural Zoology and Entomology Universit.l’ ot’ Agricultural Sciences of Athens Athens 301 - Greece SUMMARY More than 65 °%1 of the honey in Greece derives from honeydew of insects. In a research work, started in 1977 and continued until now, 32 species of insects have been identified which produce honeydew exploited by bees. All these insects belong to the order Hemiptera : Homoptera and to the superfamilies Aphidoidea, Coccoidea, Psylloidea and Aleyroidea. Among these 32 species, the most important from the point of the honey production, are : The coccids Marchalina hellenica (Gen.) and Phy.sokermes hemicryphus Dalm. and the aphids Cinara con/ini.s (Koch.) Cinara pectinatae N6rdl. and Mindaru.s abietinus Koch. INTRODUCTION Honeys are derived from flower nectar, from plants which have nectaries elsewhere (extrafloral nectaries) and from the honeydew. « The utilisation of honeydew by bees has long been recognized and honeys derived from it have considerable economic value in some parts of the world» (AUCLAIR 1963). From statistical data of honey market of the years 1975-1976 it is obvious that more than 65 % of honey production in Greece is based on honeydew. This honeydew honey according to the same statistical data, is derived from Pinus spp. (60 %) and Abies spp. (5 %) (SELIANAKIS 1978). The honeydew honey has a low percentage of invert sugar (glucose and fructose) high percentage of saccharose and other polysaccharides high pH (4,8-S,1) and it shows no crystallization during the storage. The main difference, between Pinus and Abies derived honey is based on the colour and flavour. Thus the Abies-honey is clear, and viscous and with good flavour while the Pine-honey is muddy and with inferior flavour (CODOUNIS 1962). There is also a honeydew which seems to be excreted straight from plants and appears in very small quantities usually early in spring and some times late in autumn. At these times there is frequently lack of nectar and bees exploit this honeydew, but as this is excreted in low quantities and only for a short duration its contribution to honey production is negligible. NICOLOPOULOS (1959) refers to about twenty plant species which seem to excrete directly honeydew. Recently three plants have been observed to give such honeydew which is exploited by bees, that is : Abies spp. which give honeydew during the spring, Ceratonia siliqua L. and Quercus sessiliflora Sm. in autum. The honey derived from the honeydew of the two last plants is not good in quality and as reserves for the overwintering of the colonies, they create very serious problems to the beecolonies. This has been observed to the areas of Crete and Phokis and we have not concluded yet the explanation of this phenomenon. The whole subject is under investigation. All honeydew producing insects belong to the order Hemiptera : Homoptera (Rhynchota). This group includes a large number of Coccoidea, all Aleyroidea and Psylloidea and most of the Aphidoidea and Cicadoidea (MAURIZIO, 1976). Greek beekeepers often make use of abundant honeydew by bringing their hives at the proper season into host-plants which are infested by these honeydew producing insects. Very little was known concerning these insects of Greece prior to study by NICOLOPOULOS (1965), SANTAS (1979 and 1981). In recent years a great deal of research has been done in Greece on the insects and some of the data which have accumulated are reported here. METHODS During the years 1977-1981 a country-wide survey was carried out in Greece (Fig. I). The honeydew producing insects on which the bees were observed to forage, were collected and identified. Plant hosts of these insects were also collected and identified. The survey was done in two steps : first extensive sampling of the plants to all migratory beekeeping areas in Greece was made to obtain information on the honeydew producing insects on which bees may forage, and second, detailed observations were carried out on the plants infested with honeydew producing insects to see bees to forage on honeydew. The survey carried out in the main beekeeping areas and some times after information and suggestions of skilful beekeepers on biotopes which are used in the migratory and usual beekeeping areas. These surveyed areas are : I) North part of the Euboea island, Thassos island, Chalkidiki district and South East of Crete the main Pinus-honey producing areas, in August, September, October and March. 2) The mountain of Parnis, Parnassos, Oiti, Tymphrystos Mainalon, Enos, Parnon and Ide, the main Abies-honey producing areas, in May and June. 3) The valleys of Phthiotis, Thessaly and Kopais the main glover and cotton producing areas. The observations took place when the hives were in those places by the author and another skilful beekeeper. The collected insects were transferred to the laboratory and some of them were identified by the author and other were sent to other specialists for identification. A quite large number of samples were sent to us by skilful beekeepers who had observed bees to forage on the honeydew. In addition, attempts were been made to find out the contribution of each of the honeydew producing insects, in the honey production of Greece. Thus a number of insects were found to produce honeydew exploited by bees. From these species many are probably not of great importance because the mere fact that some bees are found foraging on honeydew does not prove that they contribute significantly to the honey production. RESULTS AND DISCUSSION Thirty two species of insects producing honeydew were found to be exploited by bees in our country (Tabi. I). This number is small compared with that found in central Europe (58 known) (KUNKEL and KLOFT, 1977). These species may be divided into two groups. The first group comprises all those insects which have a great contribution to honey production in Greece. These are all the species which actually are exploited in Greece by beekeepers who transfer the hives to their biotopes. These are : Marchalina hellenica, Physokermes hemicryphus, Cinara confinis, Cinara pectinatae, and Mindarus abietinus. The second groupe consists of those species which only partially contribute to honey production or those which are not very important to the honey production, being incidental foraged for the bees. These are the rest twenty seven species of Tabl. l. It is quite possible that this division does not give an accurate estimate of the importance of these species with respect to the honey production since the bees are capable of changing their forage if the principal source is not available. Nevertheless the five aforementioned species must be regarded as important source of forage for bees. As it was estimated that the honeydew honey produced from the coniferous trees forests accounts for the 60-65 % of honey production in Greece while the contribution of broad-leaved trees and other host plants has not been estimated yet. In our country, the different species of Pinus are the main host plants fot the most important honeydew producing insects useful to honey production. The insects which produce honeydew on Pinu.s are : M. hellenica, C. palaestinensis and C. close pini. Taxonomically this species is not yet clear. Dr. G. PEMAUDIERE of Inst. Pasteur, Paris, is on the way to make a detailed analysis. It will appear from our study that M. hellenica (Fig. 2, 3) is the main source of forage for the bees since 55-60 % of honey production in our country is from this scale insect (SANTAS, 1979). This species is widely distributed in almost all pine forests all over Greece and supports the bulk of migratory beekeeping. The time of excretion of this insect is from June to following spring but the bees, depending on the area, forage on that honeydew in August, September, October and to a smaller extent in March and April (SANTAS, 1979, 1981). The exact contribution to honey production of C. palae.stinensis and C. close pini is not known, as the infestation of Pinus by these aphids is not in large areas but in planches here and there. Yet the infestation by these insects do not appear every year. This depends on the weather, entomophagous insects and other factors. Second in importance as host-plants of honeydew producing insects are the different Abies species, as they contribute, 5-l0 % of all the honey producted in Greece. The insects which produce honeydew on Abies trees are : The scales Ph. hemicryphu.s. E. sericeum and the aphids C. confinis. C. pectinatae and M. abietinus, with Ph. hemicryphus being the most important. The infestation of Abie.s trees by this scale appears more or less in large Abie.s forests. The beekeepers bring their hives to these Abies forests as most of the foraging is done in May-June and early July (SANTAS, 1981) but the exact time depends on the altitude of the forests and on the weather.